imo
Well, i was in the same prediciment (spelling?) I was looking at either a Shocker or an impulse but then i got a chance to shoot them and i didn't like the electric triggers, i never have, they just don't feel right and i've shot a few electric guns. (I'm sure alot of you will disagree and say electric our able to shoot faster, which they can, but i just dont like them, its a personal preference) Anyways, I decided to get an Autococker (2002 Stock Red w/ Vertical Feed) the first time i used it was at wasaga beach in Ontario for the TimeGate2 scenario and it was amazing, i had absolutely no problems the entire day, even running off co2. I was able to shoot 5-8 balls per second easily with no chops (this was with a regular hopper, no agitation or anything. except me shaking it when the balls jammed in the neck.) Also, i borrowed a friends freak barrel and the accuracy was just amazing.
On the negetive, i did have some pretty erratic velocities early in the day(+/- 40fps over 5 shots), but they tightened up after dinner, this may just have been from the co2.